Fuel injection nozzle assembly



y 1968 F. DE LUCA 3,382,851

FUEL INJECTION NOZZLE ASSEMBLY 'Filed April 26, 1966 2 Sheets-Sheet 1mvzmoa: FRANK DE LUCA ATTYS.

May 14, 1968 F, )5 LUCA FUEL INJECTION NOZZLE ASSEMBLY 2 Sheets-Sheet 2Filed April 26, 1966 INVENTORI FRANK DE LUCA ATTYS United States Patent0 3,382,851 FUEL INJECTION NOZZLE ASSEMBLY Frank De Luca, Thompsonville,Conn, assignor to American Bosch Arma Corporation, Springfield, Mass., acorporation of New York Filed Apr. 26, 1956, Ser. No. 545,290 9(Zlairns. (Cl. 123 -32) ABSTRACT OF THE DISt'ZLOSURE In combination withan engine having an engine cyliner head and at least one combustionchamber, an air intake passage to the valve controlled intake port ofthe combustion chamber and an elongated bore opening into the combustionchamber for mounting therein a fuel injection nozzle assembly. The fuelinjection nozzle assembly includes a nozzle having a tip adapted todirect fuel into the combustion chamber and a holder adapted to beconnected to -a fuel supply to deliver fuel to the nozzle tip. Theassembly further includes a fuel leak-off chamber to collect normal fuelleakage, passageway means directly connecting the leak-off chamber tothe air intake passage, and seal means insuring direct discharge of fuelfrom the leak-off chamber into the air intake passage.

The present invention relates to a fuel injection nozzle for injectingfiuid fuel into the cylinders of internal combustion engines and moreparticularly to a novel assembly including means for exhausting leakagefuel directly into the air intake chamber of the engine.

As is conventional in some internal combustion engine assemblies, a fuelinjection nozzle is provided for each cylinder of the assembly todischarge fuel directly into the engine cylinder. These nozzleassemblies generally comprise an elongated, generally cylindrical nozzleholder having a fuel passageway therein to direct fuel from a suitablesource to the nozzle mounted at one end of the holder. The nozzle has anaxial bore which mounts therein a valve element which is normally biasedto close the spray orifices in the nozzle tip which projects into theengine cylinder by means of a spring housed in the holder. The nozzlefurther includes an annular fuel chamber and a fuel passage connectingthe annular chamber to the fuel passageway in the holder whereby uponfuel ressure build up in the annular chamber, the valve element israised to permit fuel to be delivered through the orifices in the outerend of the nozzle tip. It has been found that there is a certain amountof fuel leakage which bypasses the valve element and returns to thespring chamber which must be vented for proper operation of the fuelinjection nozzle. Accordingly, most of these assemblies include aleakoif channel in the holder communicatin g with the spring chamberwhich, through suitable fittings and a line, is connected back to thefuel supply source. In some instances, the leakotf port cornmunciatesdirectly with a fuel leakolf passageway in the holder. It has been foundthat even if the parts are finished to provide very close tolerancesbetween the movable parts of the fuel injection nozzle, such as thevalve and the nozzle bore, nevertheless, there is a certain amount offuel leakage in the operation of the nozzle and in order for the nozzleto operate properly, this leakage must be vented.

As is readily apparent, the additional piping and fittings required forthe fuel leakoif a swell as the formation of the leakoif channel in theholder add to the cost of the nozzle assembly. Moreover, the returnlines and fittings take up valuable space in an already crowded area ofthe engine and nozzle assembly.

The present invention provides a new and improved leakoff arrangementwhich eliminates the undesirable features and drawbacks of the priorsystems discussed above. In accordance with the present invention, aleakoff port is provided in the cylinder head communicating at one endwith an annular chamber defined between the holder and opening in whichthe nozzle assembly is mounted which receives the leakoff fuel and atits opposite end with the intake port just above the valve seat of theair intake valve.

Still another object of the present invention is to make a more compactfuel injection nozzle assembly by eliminating the axially extendingconventional leakotf passageway in the nozzle holder.

These and other objects of the present invention and various featuresand details of the operation and construction thereof are hereinaftermore fully set forth with reference to the accompanying drawings,wherein;

FIG. 1 is a fragmentary sectional view through an engine block showing afuel injection nozzle and leakage fuel bypass combination in accordancewith the present invention;

FIG. 2 is an enlarged fragmentary section-a1 view through a portion ofthe fuel injection nozzle;

FIG. 3 is a sectional view taken on lines 3-3 of FIG. 2;

FIGS. 4 and 5 are sectional views similar to FIG. 3 showing otherembodiments of a fuel injection nozzle and leakage fuel bypasscombination in accordance with the present invention.

Referring now to the drawings, there is illustrated in FIG. 1 a fuelinjection nozzle assembly '10 mounted in an elongated bore 11 in anengine cylinder head 12 with the tip portion extending into the pistonchamber 14. The engine includes an air intake valve 13 mounted in an airintake chamber or passage 15. The fuel injection nozzle assemblycomprises an elongated, generally cylindrical holder 16 and a nozzle 18mounted on one end of the holder by means of a cap nut 29.

The nozzle, as best illustrated in FIG. 2, comprises an upper generallycylindrically body portion 24 and an elongated nozzle shank 26 etxendingfrom the body portion. The fuel nozzle has a stepped axial bore 28comprising an upper bore section 28a and a lower bore section of smallersize 28b, the juncture of the bore sec tions being enlarged to define anannular fuel chamber 30. A valve member 32 is mounted in the axial borehaving a conical tip 34 which seats on a conical seat 36 at the terminalend of the nozzle tip 26. This valve element 32 is normally biased to aclosed position up against the seat 36 by means of a spring 40 housed inthe spring chamber 42 in the holder 16, the spring chamber 42 also inthe present instance defining a fuel leak-off chamber to collect normalfuel leakage.

Fuel is delivered from a suitable supply source through an inlet 44 atthe upper axial end of the holder 16 through an elongated fuelpassageway 46 in the holder which communicates at its inner terminal endwith a short passage 48 in the nozzle body which in turn, as illustratedin FIG. 2, terminates in the fuel chamber 30. By this arrangement, whenfuel pressure builds up in the annular chamber 30 and acts on thetapered shoulder 50 of the valve element 32, and is of a suificientdegree to overcome the force of the spring 40, the valve 32 is raisedwhereby the fuel passes from the chamber 30 down through the annularspace between the valve and the bore section 281') through the orifices52 in the tip end of the nozzle and into the engine cylinder orcombustion chamber.

In the normal operation of the fuel injection nozzle there is a certainamount of leakage between the valve and the bore in which the valve ismounted, and as noted above, it is necessary to provide venting meansfor the leakage fuel for proper operation of the fuel injection nozzle.More specifically, the fuel leakage passes between the upper boresection 28a and the valve element into the spring chamber 42. Inaccordance with the present invention, means is provided for venting theleakage fuel and exhausting it directly to the intake manifold orchamber 15 of the engine. To this end there is provided in the presentinstance a short radial channel 60 in the holder which communicates atone end with the spring chamber 42 and at its outer terminal end with anannular recess 62 provided by an undercut on the holder between theholder and the wall of the bore 11 in which the nozzle assembly ismounted. This annular recess 62 as best illustrated in FIG. 2communicates directly with the air intake chamber 15 through a bypassport 76. Sealing means are provided above and below the annular recess62 so that the leakage fuel is exhausted directly into the air intakemanifold 15. The sealing means comprises, as best illustrated in FIG. 1,an annular sealing ring 72 which seats in a groove in the holder abovethe recess 62 and a sealing disc '74 between the lower face of the capnut 21) and the annular shoulder at the juncture of the step of theopening 11 in the engine block 12.

By this arrangement, during operation of the valve fuel leakage enteringinto the Spring chamber 42 passes through the radial port 60, annularrecess 62, bypass port 70 into the air intake manifold 15. It is notedthat in the air intake manifold 15, fuel enters just above the intakevalve 13 where the air velocity is relatively high so that the leakagefuel is well aspirated. This aspirated leakage fuel is then drawn intothe engine cylinder on the intake stroke whereby some precombustionreactions take place prior to injection of the main fuel charge into thecombustion chamber.

Furthermore, this leakoif bypass arrangement is a much simplerarrangement than the previously known methods employing a leakoffchannel in the nozzle holder, fittings on the nozzle holder and linedirecting the leakage fuel back to the main fuel supply. Elimination ofthese parts greatly simplifies construction and overall cost of theassembly.

There is illustrated in FIGS. 4 and other embodiments of fuel injectionnozzle assemblies having leakage fuel Venting means in accordance withthe present invention. The fuel injection nozzle assembly of FIG. 4 isgenerally identical to that described above and comprises an elongatedgenerally cylindrical holder 116 and a nozzle 118 mounted at one end ofthe holder by means of a cap nut 120, the entire assembly being mountedin an elongated bore 111 in an engine cylinder head 112. A valve member132 is mounted in an axial bore 128 in the nozzle 118 and is normallybiased to a closed position by means of a spring actuator 140 mounted ina spring chamber 142 in the lower end of the holder 116. As illustrated,the bore 111 is slightly larger than the cross section of the fuelinjection nozzle assembly to provide an annular space 119 which space issealed at opposite ends by sealing means including an O-ring 172mounted, in the present instance, in a recessed groove 173 in the wallof the bore 111 and a sealing disc 174. This annular space 119communicates with a fuel leakage bypass port 170 in the engine cylinderhead 112 which discharges into the air intake chamber of the engine. Inthe present instance the leakage fuel is directed into the bypass port179 by counterborin-g the inner end of the upper bore section 128a toprovide an annular recess 131 in the inner axial end face of the nozzlebody portion 116 which recess 131 communicates with the annular space119 between the fuel injection nozzle assembly and the bore 111 througha radial slot 133 in the inner axial end face of the nozzle body anddrilled hole 135 in the holder. By this arrangement in the operation ofthe fuel injection nozzle assembly, any leakage fuel bypassing the valveelemen an pp ial bore section passes into the annular recess 131 andthrough the radial slot 133 to the annular space 119 surrounding theassembly and from there into the bypass port 178 and air intake chambercommunicating With the port 170.

The fuel injection nozzle assembly of FIG. 5 also includes a holder 216and a nozzle 218 mounted on one end of the holder by means of a cap nut220. The bore 211 is engine head 212 in which the fuel injection nozzleassembly is mounted is slightly enlarged to define an annular space 219which comunicates with the air intake chamber through a bypass port 270.The annular space 219 is sealed by an O-ring in a recessed groove in thewall of the bore 211 as in the arrangement of FIG. 4, and a sealing disc274. The assembly further includes a valve element 232 normally biasedto a closed position by means including a biasing spring 246 housed in aspring chamber 242 in the lower axial end of the holder. Leakage fuel isdirected to the tair intake chamber by means including, in the presentinstance, a short radial channel 250 in the holder and a short axialconnecting leg or channel 252 which connects the short radial channelwith the upper end of the spring chamber 24-2, the channel 251icommunicating with the annular space 219.

While particular embodiments of the present invention have beenillustrated and described herein, it is not intended to limit theinvention and changes and modifications may be made therein within thescope of the following claims.

I claim:

1. In combination with an engine having an engine cylinder need and atleast one combustion chamber, an air intake passage to the valvecontrolled intake port of the engine combustion chamber and an elongatedbore opening into the combustion chamber for mounting therein a fuelinjection nozzle assembly, the fuel injection nozzle assembly in thebore including a nozzle having a tip adapted to direct fuel into thecombustion chamber and a holder adapted to be connected to a fuel supplyto deliver fuel to the nozzle tip, said assembly including a fuelleak-off chamber to collect normal fuel leakage, passageway meansdirectly connecting the leak-off chamber to the air intake passage andseal means insuring direct discharge of fuel from the leak-off chamberinto the air intake passage.

The combination as claimed in claim 1 wherein said fuel injection nozzleassembly comprises an elongated holder and a nozzle mounted at one endof the holder, a valve element mounted in an axial bore in the nozzle,biasing means mounted in a leak-off chamber in the holder for normallyurging the valve element to a closed position and wherein said pasagewaymeans connects the leak-off chamber to the air intake passage.

3. The combination claimed in claim 2 wherein said passageway meansincludes means defining an annular recess in the holder, a radial portconnecting the leak-off chamber with the annular recess and a channel inthe engine cylinder head directly connecting the annular recess to theair intake passage.

4;. The combination as claimed in claim 3 wherein the elongated bore inthe engine cylinder head is of a larger cross section than the outerdiameter of the holder-nozzle assembly to provide an annular spacetherebetween with which the passageway means communicates.

5. The combination as claimed in claim 4 wherein said seal means isdisposed on opposite sides of said annular recess whereby leakage fuelis directed into the connecting channel.

6. The combination as claimed in claim 5 wherein the seal meanscomprises a sealing ring mounted in a groove in the holder and a sealingdisc at the step in the opening in the engine cylinder head againstwhich a cap nut securing the nozzle to the holder abuts.

7. The combination as clamied in claim 2 including an annular recessprovided by counterboring said axial bore in the nozzle at the axial endface thereof adjacent 5 the holder and a slot in said axial end facecommunicating at one end with said recess and at its opposite end withsaid passageway means.

8. The combination as claimed in claim 2 including a short radialchannel in said holder communicating with said pasa'geway means and ashort axial connecting channel which connects the radial channel withthe upper end of the leak-off chamber.

9. The combination as claimed in claim 8 wherein said seal meanscomprises a sealing ring mounted in a 6 groove in said bore for saidfu'el injection nozzle and a sealing disc at the step in the opening inthe engine cylinder head against which the cap nut securing the nozzleto the holder abuts.

References Cited UNITED STATES PATENTS 2,627,254 2/1953 Juhasz 123322,858,813 11/1958 Haas 123-32 LAURENCE M. GOODRIDGE, Primary Examiner.

